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HEXAPODS. A hexapod robot , somewhat recent innovation in robotics, is a mechanical vehicle that walks on six legs. Since a robot can be statically stable on three or more legs, a hexapod robot has a great deal of flexibility in how it can move. HEXAPOD WALKING.
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A hexapod robot , somewhat recent innovation in robotics, is a mechanical vehicle that walks on six legs. • Since a robot can be statically stable on three or more legs, a hexapod robot has a great deal of flexibility in how it can move.
HEXAPOD WALKING • A rectangular 6-legged robot can lift three legs at a time to move forward, and still retain static stability. • How does it do that? • It uses the so-called alternating tripod gait, a biologically common walking pattern for 6 or more legs.
HEXAPOD WALKING • Characteristic of this gait: • one middle leg on one side and two non-adjacent legs on the other side of the body lift and move forward at the same time, • the other 3 legs remain on the ground and keep the robot statically stable.
HEXAPOD AND INSECT WALKING • Roaches move this way, and can do so very quickly. • Insects with more than 6 legs (e.g., centipedes and millipedes), use the ripple gate. • However, when these insects run really fast, they switch gates to actually become airborne (and thus not statically stable) for brief periods of time
Biologically inspired • insects • Potentially very stable as the motion of one leg usually does not affect vehicle stance. • Fairly simple to come up with a control algorithm
HEXAPOD WALKING • Torso servo supports the two hip servos. • Legs are lifted and dropped by hips while side to side motion achieved by torsos.
WALKING ALGORITHM • Step 1 • – legs 1,4,and 5 down, legs 2,3 and 6 up. • Step 2 • – rotate torso 7 and 9 counter-clockwise, torso 8 clockwise. • Step 3 • – legs 1,4 and 5 up, • – legs 2,3, and 6 down. • Step 4 • – rotate torso 7 and 9 clockwise, torso 8 counter-clockwise. • Goto step 1
ALTERNATING TRIPOD GAIT • Walking gaits were first reported by D.M. Wilson in 1966. • A common gait is the “alternating tripod gait”. • Commonly used by certain insects while moving slowly.
Build Your Own Robot • 3 Servo Hexapod • http://letsmakerobots.com/node/4947 • Useful books • Insectronics: Build Your Own Robot by Karl Williams.